3" pipe to stock exhaust??

[ned]

Hi all,

i am onto my 2nd Skyline, and I have to say that I am really enjoying the lower in-cabin noise with the stock exhaust compared to the last car. The last R33 had a Hitech catback which was good, but I now realise it also raised the background noise a fair bit.

With the new car, I have replaced the turbo pipe, and it has a 3" Cat. Since it seems important to give the exhaust gases as little resistance as possible until they have cooled, I was wondering what effect it would have if I changed the pipework from the catback to 3" in mild steel, then let the pipe taper to fit the stock GTR rear exhaust?

I am hoping that the larger pipe volume reduces the resistence, and lets the exhaust gases cool before entering the stock rear box where it now is less of a bottleneck on the system.

Any one with experience in exhausts have an opinion?

Thanks

Ned

[silver33]

Hey Ned,

Why not try a second hand Japanese cat-back system?

You can get them for as little as $450. Depending on the brand and model, some are quieter than the Hi-Tech exhausts.

[ned]

HI Silver 33,

My reason for keeping the stock exhaust wasnt cost related, but I probably will get a 2nd hand exhaust this time, however since you never know how it will sound until you stump up the cash and get it fitted, its still a lucky dip.

I dont mind a snarl at higher revs, so long as its inaudible at commuting, and highway cruising speeds.

Ned

[silver33]

Hey Ned,

I understand your dilema.

I too have a 3" dump off the turbo upto the cat but have a stock exhaust from the cat back.

I use to have an exhaust from Hi-Tech on my previous car and the exhaust note at cruising speed also got to me., which is why I have not upgraded the cat back exhaust. I like the quietness of the stock system but I'm sure there is alot of ponies to be had by replacing it with a more free flowing system.

If I was to upgrade, a Jap cat back system that is JASMA approved would be the only systems I would consider.

One of my friends brothers has an R33 GTS-T with a Jap system. I've only been in it once and it was very quiet - could not believe it. I'll see if I can get the brand and model.

[BHDave]

It's a good idea to increase the size of the pipe off the dump as it allows the hot turbulent air to to get away quicker.

There is a slight gain to be had in power and response but it isn't massive. You will also get a little more noise/resonance over stock.

BTW JASMA cat back systems are the shit. I've had two now, a 65mm Kakimoto which was very quite until pushed hard and now a brand unknown 80mm cat back which is quiter than the 65mm system. There is still a bit of background noise at freeway speeds though.

[akeenan]

BTW JASMA cat back systems are the shit

jasma systems are the same as any other system.

do a search on these..

i had a trust system which was jasma approved and it was super loud 100 and soemthing db...

[ned]

Hi BH DAve,

I had heard that the JASMA exhausts were good but as akeenan points out there are a variety of them which all can have the acreditation mark so long as they meet the reg's (not all related to noise levels I understand).

I'm still interested in the lareg pipe to stock exhaust, if anyone has experience?

Ned

[BHDave]

Noise is actually one of the main considerations in getting the JASMA plate.

A JASMA stamped exhaust is the Japanese version of an ADR compliant exhaust, except JASMA is an independent association. It isn't going to get the tick if it doesn't meet all the requirements, such as build quality, noise output, emissions, and probably others.

It's a fair bet your TRUST system was getting old and worn out akeenan (and no I'm not having a go at you) but exhausts do get louder over time as the steel wool/fiberglass packed in the mufflers starts burn off eventually.

If someone does have a brand new JASMA stamped exhaust thats noisey as hell then I would like to hear about it, I won't argue about it if I'm wrong.

Cheers

Dave

[Steve]

I had a full N1 system (just a big pipe, small muffler) and it was bloody loud - gave me headaches.

I got a heap of quilting material from spotlight, and lined the boot and behind the rear seat - that made it alot more bearable and only cost about 5 dollars for the material and same for some spray glue.

I decided to get a quiet system, to avoid any attention from the plods, so went out and bought a Nismo dual muffler 80mm cat back. It is alot quieter, but still barks in anger:)

The other big difference I noticed though, was a very prominent loss in power, and more lag - my car felt very sluggish and lethargic, but it was quieter.

Bottom line is, performance has a price, not always just dollars.

[Evil]

I just got a Fujitsubo Power Getter (3" pipes) it's not too loud (although I love loud exhausts) but depending on how I drive it the noise varies. If I take off slowly and change gears early it is quiet. If I punch it, the noise peaks at about 2500-3000rpm then drops off again. When freeway driving there is no drone. It also depends on the res and muffler (and the tip). I though the Hi-Tech stuff was supposed to be quiet (and legal) :confused:

[nemz]

i have hks super dragger 3" all the way witha 5" tip and it is very quiet

[cav]

loud is good it lets you feel what you are driving, and rb turbo motors sound awesome with a nice exhaust.

[Ronin 09]

Originally posted by BHDave

A JASMA stamped exhaust is the Japanese version of an ADR compliant exhaust, except JASMA is an independent association. It isn't going to get the tick if it doesn't meet all the requirements, such as build quality, noise output, emissions, and probably others.

It's a fair bet your TRUST system was getting old and worn out akeenan (and no I'm not having a go at you) but exhausts do get louder over time as the steel wool/fiberglass packed in the mufflers starts burn off eventually.

If someone does have a brand new JASMA stamped exhaust thats noisey as hell then I would like to hear about it, I won't argue about it if I'm wrong.

Cheers

Dave

Dave, i got a brand new Trust 4" cat back (and now have a full system). It was tested at 108dB... I wouldn't take too much from the Jasma approval in terms of noise levels

[akeenan]

ronin09 i was waiting for your reply

It's a fair bet your TRUST system was getting old and worn out akeenan (and no I'm not having a go at you) but exhausts do get louder over time as the steel wool/fiberglass packed in the mufflers starts burn off eventually.

i dont mind if people have a go at me i believe the exhaust wasnt too old either but i guess icould be wrong. but i dont believe a straight pipe with a huge cannon muffler, this cannon muffler being about 5 inches wide with a couple of holes around the inside would be able to make the system quiet "er"

[silver33]

Hey Ned,

If you do decide to get 3" piping leading into the stock muffler, let us know of any improvements or degradation. It would be very interesting to hear your comments.

[rs73]

In general, most 3" system would be loud. They can all be JASMA certified as I think JASMA's max db limit is still higher than our EPA standard. (One exhaust shop even laughed & called me crazy to have 3" system - they say I better have a 500HP car with that!)

However, you can do visual inspection to save you some headache later. Just by looking at the design, any canon style muffler (such as Apex'i N1 style) would likely be a bit loud unless you chuck in a tail silencer.

Non canon style muffler would be a step quieter, such as Trust MX (have one on my car) with a proper mid resonator and end muffler section like stock ones except for a 114mm tip. HKS Super Dragger would be in this category too IMO.

Some other exhaust would even be quieter and only sounds a bit louder than stock. I can't think of many but on top of my head would be something like Nismo Weldina, Kakimoto (heard one before - very quiet) or Fujitsubo

Hope this helps.

PS: Ronin, which Trust exhaust you got? Do you know which model, as there are many varieties and some are louder than the others.

[Ronin 09]

rs73, it is either a Power extreme II or a Power Evolution II - i think it is the latter.

[rs73]

I think I know which one it is... that'll be the same design with Apex'i N1 & GT Spec.

They'll obviously be louder than Trust MX. Do they come with tail silencer like N1 & GT? Maybe that'll cut the noise down a bit.

[Steve]

Originally posted by rs73

..... (One exhaust shop even laughed & called me crazy to have 3" system - they say I better have a 500HP car with that!)......

:bahaha: those old school guys just woundnt have a clue, obviously time to run a mile if you hear that.

With so many good second hand exhausts around these days - I bought a Nismo cat back that retails for over $3000 for $700 and it was in near new condition and excellent quality (even has a carbon fibre surround on the tip, gotta love the rice touches:D) - its hard to understand why you would buy a aust made exhaust only to pay more and get less.

[Evil]

Originally posted by rs73

Some other exhaust would even be quieter and only sounds a bit louder than stock. I can't think of many but on top of my head would be something like Nismo Weldina, Kakimoto (heard one before - very quiet) or Fujitsubo

I agree there. My Fujitsubo Power Getter is not too loud for an exhaust with 3" pipes and a 4 1/2" tip.